Surgeons performing arthroplasty on painful, misshapen, arthritic hand joints do not have the choice of replacing the damaged joint with a prosthesis that will restore near natural movement, as they would if a hip joint were being replaced. There are no effective finger joint replacements available. Past attempts to produce hinge type joints have failed because the minute pin of the hinge bore all the load placed on the finger leading to its early breakdown. The innovative Arthroflex concept is based on the fact that little load is applied when the fingers are moving. When a load is applied there is little or no movement. By mounting the pin elastically, loading will cause large mating surfaces on the rigid stems to come in contact, thus taking the load off the pin. Proposed research is to demonstrate feasibility of the Arthroflex concept. Kinematic and finite element analysis (FEA) will be used to analyze forces on joints during normal hand usage. Test data to be produced will be incorporated in the FEA program to formulate the ultimate mechanical design for prototype development and clinical testing during Phase II.